how soon does vitamin b12 injection start working This Is Long It Takes For A To The Science Behind Vitamin B12:

This means its illegal and extremely unsafe to buy it from any website that doesnt ask for a valid prescription from a qualified prescriber

Vitamin B12 There is four types of parenteral Vitamin B12 available: Cyanocobalamin 100 mcg/ml and 1000 mcg/ml best used as IM to prevent rapid loss via kidneys Hydroxycobalamin IM (compounded 1000 mcg/ml or more) known as long acting B12 (binds better to plasma proteins than cyanocobalamin) Methylcobalamin IV (compounded 1000 mcg or more up to 5000 mcg/ml) Adenosylcobalamin IV Common dose is 1000 mcg IM or IV Vitamin B12 as hydroxycobalamin is synthesized exclusively by microorganisms and is found in the liver of animals bound to protein as methylcobalamin = metabolically active form of Vitamin B12 Hydroxycobalamin is a chelator of cyanide and is used in cyanide poisoning Hydroxocobalamin is most generally used for vitamin B12 replacement therapy and is considered the drug of choice for vitamin B12 deficiency by the Martindale Extra Pharmacopoeia (Sweetman, 2002) and the World Health Organization (WHO) Model List of Essential Drugs

Strict vegetarians who eat no animal products (vegans) need supplemental vitamin B 12 to meet their requirements

The effects of vitamin B-12s mechanism of action within the human body include production of new red blood cells, maintenance of healthy neurological cells, and synthesis of DNA